Mrs May said she would make it easier to deport foreign terror suspects and "restrict the freedom and movements" of those who present a threat.

In what would be one of her last appearances before the general election on Thursday, she said she would consider longer prison sentences for terror offences, more stringent rules on deporting those who espouse terror, and new controls on those who are seen as a potential threat even if there is not evidence to take them to court.

Addressing activists in Slough on Tuesday evening, she did not make any specific new policy proposals but said: "I mean longer prison sentences for those convicted of terrorist offences.

"I mean making it easier for the authorities to deport foreign terrorist suspects back to their own countries.

"And I mean doing more to restrict the freedom and movements of terrorist suspects when we have enough evidence to know they are a threat, but not enough evidence to prosecute them in full in court.

"And if our human rights laws get in the way of doing it, we will change the law so we can do it."

BBC political editor Laura Kuenssberg said sources suggested that if elected Mrs May could consider curfews, controls on who people could visit and suspects' access to communications.

The Conservative manifesto committed to remaining in the European Convention on Human Rights - which is separate to the EU - for the whole of the next Parliament.

Conservative sources said they would not withdraw from the ECHR but would seek opt-outs called "derogations" from certain aspects.

The opposition Labour Party said that was "not the message that we should be sending". Its leader Jeremy Corbyn said the right response was to "halt the Conservative cuts and invest in our police and security services and protect our democratic values, including the Human Rights Act."

And Shadow Attorney General Baroness Chakrabarti said the PM had "been banging on about her dislike for human rights for a very long time".

"That's not the message that we should be sending to communities or to terrorists today."